Cross reference
Numbers 4:27
27 From the mouth of Aaron and his sons the Gershonites will have word about all the things they are to do and take up; you are to give them their orders.
Luke 1:70
70 (As he said, by the mouth of his holy prophets, from the earliest times,)
1 Corinthians 11:2
2 Now I am pleased to see that you keep me in memory in all things, and that you give attention to the teaching which was handed down from me to you.